Carbon coated magnetite nanoparticles with improved water-dispersion and peroxidase-like activity for colorimetric sensing of glucose

Nanomaterials-based enzymatic mimics have recently received considerable attention due to their superior properties over natural enzymes. Particularly, great efforts have been made to the fabrication of enzymatic mimics based on carbon matrix-based hybrid nanocomposites because of their improved dispersion, stability and catalytic activity compared with naomaterials alone. In this work, a new peroxidase mimic based on carbon coated magnetite nanoparticle (Fe3O4@C) with improved water-dispersion and peroxidase-like activity was presented for the first time. Unlike conventional hybrid nanocomposites, Fe3O4@C is a typical core-shell structure in the nanoscale regime and possesses the properties of easy preparation, super water-dispersion and excellent stability. Owing to the presence of carbon shell, Fe3O4@C showed an enhanced peroxidase-like activity as compared with its two components. As a peroxidase mimic, the catalytic kinetic of Fe3O4@C follows Michaelis-Menten behaviors and shows stronger affinity to peroxidase substrates than horseradish peroxidase. On the basis of these findings, a simple colorimetric method for glucose detection was developed by combining the catalytic reactions of Fe3O4@C and glucose oxidase. Additionally, the proposed method was successfully applied to determine the levels of glucose in serum and urine samples and showed a satisfactory result. (C) 2015 Elsevier B.V. All rights reserved.